Filter an Array of strings using Filtered String and Remove from Original Array

Question

I want to remove some elements from the array containing the word Evil (filterString).

let guests = ["Partner", "Evil Nice Relative 1", "Nice Relative 2", "Evil One", "another evil", "another one", "another evil is here", "strange Evil is here", "someone Nicer", "Ugly Evil Bad"];

const filteredArray = [];
const filterString = "Evil";

function checkEvil() {
    guests.filter((element, index) => {
        if (element.toLowerCase().indexOf(filterString.toLowerCase()) !== -1) {
            console.log(index);
            guests.splice(index,1);
        } else {
            filteredArray.push(element);
        }
    });
    console.log(guests);
}

Here is what I get for the original array (guests):


    ['Partner', 'Nice Relative 2', 'another evil', 'another one', 'strange Evil is here', 'someone Nicer']

Just want the guests array updated once the desired string (Evil) is filtered.

Look into `filter` and `includes` or `indexOf` methods, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter — Nenad Vracar, Dec 12 '21 at 14:51
Somehow the original code didn't show up here. Edited the question. — Tahir, Dec 12 '21 at 14:55
Look into how filter method works, it returns new array of elements and when the output of callback is true that element is returned, so you don't need to use additional arrays. — Nenad Vracar, Dec 12 '21 at 14:58

DecPK · Accepted Answer · 2021-12-12T15:17:48.540

1

Since you want to mutate the original array then you can do as:

let guests = [
  "Partner",
  "Evil Nice Relative 1",
  "Nice Relative 2",
  "Evil One",
  "another evil",
  "another one",
  "another evil is here",
  "strange Evil is here",
  "someone Nicer",
  "Ugly Evil Bad",
];

const filterString = "Evil";

function checkEvil() {
  for (let i = guests.length - 1; i >= 0; i--) {
    const element = guests[i];
    if (element.toLowerCase().indexOf(filterString.toLowerCase()) !== -1) {
      guests.splice(i, 1);
    }
  }
  console.log(guests);
}

checkEvil();

1) You can easily achieve the result using filter and match as:

const arr = [
  "Partner",
  "Nice Relative 2",
  "another evil",
  "another one",
  "strange Evil is here",
  "someone Nicer",
];
const result = arr.filter((s) => !s.match(/evil/i));
console.log(result);

2) You can also do this using forEach and match as:

let guests = [
  "Partner",
  "Evil Nice Relative 1",
  "Nice Relative 2",
  "Evil One",
  "another evil",
  "another one",
  "another evil is here",
  "strange Evil is here",
  "someone Nicer",
  "Ugly Evil Bad",
];

const filteredArray = [];
const filterString = "Evil";

function checkEvil() {
  guests.forEach(element => {
    if (!element.match(/evil/i)) filteredArray.push(element);
  });
}
checkEvil();
console.log(filteredArray);

edited Dec 12 '21 at 15:17

answered Dec 12 '21 at 14:52

DecPK

24,537
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Somehow the original code didn't show up here. Edited the question. – Tahir Dec 12 '21 at 15:02
@Tahir Nothings change, so you can still use filter and match here – DecPK Dec 12 '21 at 15:08
@Tahir Another answer added. Have a look – DecPK Dec 12 '21 at 15:12
But I do want to update the original array **guests**. – Tahir Dec 12 '21 at 15:12
If you want to update the original array then why are you using `filteredArray` – DecPK Dec 12 '21 at 15:14
Just for test purposes. I will have some other operations on the **guests** array so I need that one to be updated. – Tahir Dec 12 '21 at 15:17
@Tahir another solutin added. Hope this is what exactly you want... – DecPK Dec 12 '21 at 15:18
Thanks @decpk. Exactly what I wanted. Thanks for your help. – Tahir Dec 12 '21 at 15:21

score 1 · Answer 2 · answered Dec 12 '21 at 14:59

1

define a pattern and then filter by it

var arr = ['Partner', 'Nice Relative 2', 'another evil', 'another one', 'strange Evil is here', 'someone Nicer'];
const PATTERN = 'EVIL';
arr = arr.filter(str => str.toUpperCase().indexOf(PATTERN) === -1);

answered Dec 12 '21 at 14:59

PiwiTheKiwi

129
1
14

score 0 · Answer 3 · answered Dec 12 '21 at 14:58

0

<script>
    var list = ['Partner', 'Nice Relative 2', 'another evil', 'another one', 'strange Evil is here', 'someone Nicer'];
    var new_list = [];

    for(var i=0; i<list.length; i++) {
        if(!list[i].toLowerCase().includes('evil')) {
            new_list.push(list[i]);
        }
    }

    console.log(new_list);
</script>

answered Dec 12 '21 at 14:58

Gamer In The Game

256
1
11

Let's say beginner technique ) – Gamer In The Game Dec 12 '21 at 14:59

score 0 · Answer 4 · answered Dec 12 '21 at 15:24

You can filter your array where the value of each doesn't contain 'evil' word:

const arr = ['Partner', 'Nice Relative 2', 'another evil', 'another one', 'strange Evil is here', 'someone Nicer'];
const filteredArr = arr.filter(val=>!val.toLowerCase().includes('evil'))
console.log(filteredArr)

Filter an Array of strings using Filtered String and Remove from Original Array

4 Answers4